


Brotherly love

by Saita_the_Kirin



Category: Undertale (Video Game)
Genre: Loss of Virginity, M/M, Masturbation, Sibling Incest
Language: English
Status: Completed
Published: 2018-12-03
Updated: 2018-12-15
Packaged: 2019-09-06 11:07:47
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,926
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16831417
Author URL: https://archiveofourown.org/users/Saita_the_Kirin/pseuds/Saita_the_Kirin
Summary: Papyrus walks in on Sans as he pleasures himself and runs off embarrassed. Sans decides to try and talk to him about it and it turns to something more.PapyrusxSans





	1. Chapter 1

**Author's Note:**

> I needed something different so I decided this would be fun to try. I know this isn't my normal style of story and all but I feel like I needed to have a step outside of the norm. I love Undertale so I thought I'd add this to the pot. I tried to keep both in character as much as I could but I'll see if people like this and see about adding more in the future, maybe a Grillby x Sans. anyways expect any corrections needed.
> 
> ~Enjoy

I jerked awake shocked out of sleep by an unbearable heat. I ran my bony wrist across my skull as I felt a warm blush radiating from my cheeks. “what the…” I looked down to see the raised bump under my blanket and just stared at it for a moment.

Oh great, I have a 'boner'.

I chuckled at my very 'humerus' joke then sighed. This happened from time to time, you’d think that being a skeleton I wouldn’t have this sort of problem, with the lack of skin and blood and all but no. Being a monster I was blessed with magic.

My magic normally took whatever form I chose, be it an attack or one of my shortcuts. Every now and then it took the form of well, something else.

I grunted softly and pulled the blanket aside, it was already too hot in here for that to be of any use. I glanced towards the wall I shared with my brother and waited a second. Paps normally had a soft snoring that bleed through the thin walls, normally this was comforting. Just knowing that he was sleeping soundly reassured me that he was ok but right now it just made me nervous.

It would just kill me if he walked in on me while I was rubbing one out, had a few too many close calls already. Once I was sure he was going to stay asleep I slipped down my pants and looked at my member with a sigh. I grabbed it and gave a few lazy strokes, I had to bite my shirt to keep from moaning out loud.

I set a slow comfortable pace for myself and simply let my mind wonder. What was I going to do today? Was there going to be another human today or was I Mmh! going to get a break? Maybe I would go visit the door and see if my knock knock buddy was Hmnn! there.

It was getting hard to concentrate now, the warm tingling between my legs was turning into a painful throbbing. My thoughts were beginning to blur as I picked up the pace. “oh fuck!”

Dammit. What was I thinking about again? Oh man this feels so good, it feels warm, it feels… off. Somethi- “SANS! Brother are you alright?!” My soft moaning turned to a high squeak as I heard Papyrus bang on the door loudly.

“um papyrus! i’m fine bro no need to worry” He continued to bang on the door and turn the knob furiously. “Sans! I could hear you from my room! I’m coming in brother!” “no paps wait!”

I didn’t get a chance to finish as he kicked the door open, the door had actually shattered from the force of the kick as he quickly ran into the room and looked towards me in the dark.

I scrambled to grab the blanket to try and save myself some level of dignity but it was all for not as he stared directly at me. His face was dumbfounded before he quickly went bright red and started stuttering. I just looked back at him, I was mortified. “... i can explain”

That seem to break him free from his trance, he threw an arm over his eyes with a garbled mix of an apology and to excuse him. “no paps wait! i’m sorry!” I quickly pulled on my shorts with a pained grimace and grab one of my shirts from the floor and quickly ran out into the hallway only to see Papyrus bolt straight into his room and slam the door shut.

I walked to the door and set my head to it quietly. I could hear him mumbling to himself “Oh lord why did I break in the door?! I saw him masterbating! I’m his brother, I’m not supposed to see or think of him like that. Oh no not now! … A shower, yes a shower will help. I’ll be a good brother.” I could hear him walking to the door so I softly wrapped my knuckles against his door.

I heard what I thought was him tripping over something, I couldn’t imagine what it was, he always keep his room so clean after all. I took a deep breath and continued “papyrus, paps. can i come in so we can talk please?” 

I felt the blush on my cheeks burn more brightly as he told me to come in. I opened the door only to find the room was empty. “paps?” “I’m over here brother.” I looked to the source of the noise which happened to be coming from the closet.

“um papyrus. please come out so we can talk, i know this is awkward but i can’t talk to you through the door like i do with some other person so please, come out.”

I stood there for what felt like forever, it was about three minutes in reality before he tentatively cracked the door open to look at me. His face had gone bright red which contrasted nicely with my blue one. Unfortunately for the both of us, the thing is, is that my eye level is only about waist high compared to him.

I decided to stay quiet about that and forced myself to pull my eyes up to his face. He refused to make eye contact with me and I couldn’t honestly blame him for that. Welp, only one thing to do now.

“so, you happy to see me or-” “SANS!!!! Of all the times you choose to make a joke you choose now?! And that!!” I smiled as he stomped his feet while he sputtered angrily at me.

“look paps i’m sorry about what happened. can we talk please?” He rolled his eyes and opened the door and walked over to his race car bed and sat down then patted the spot next to him. I joined him and sat down softly trying to be careful of the raging hard on between my legs, it was getting to be really painful now and Papyrus wasn’t looking any more comfortable than I was.

“Look brother, I’m sorry. I don’t mean to be like this I don’t even know why I can’t keep this disgusting lust of mine under control.” He looked so upset over this, I grabbed his knee and squeezed, he looked at me and I smiled.

“i don’t mind paps.” He looked at me for a minute before he grabbed me and pressed are lipless mouths together. I pulled his pajama shirt off as he began tugging at my shirt I pulled back a second to take off my shirt before I pulled him into a deeper kiss as we laid back onto his bed.

“oh paps you have no idea how bad i want this, how bad i need this” Papyrus thrusted his hips up against mine, the grinding of his magic up against mine about had me come then and there.

“Sans… how do you want to do this? I mean you have such a low HP it could make this rather, unsafe.” I looked at him and considered what he said for a moment while rubbing along the scar on his neck.

I had lost him so many times.

“i think i’ll be ok as long as we’re not too rough” Papyrus rubbed the scar along my chest. That huge scare was a grim reminder of what could happen today and probably why it was better not to wait.

I rubbed my bony hand along his face, looked into his eyes. I want this and he wants it too. I stripped off my pants which encouraged him to do the same.  
“So; I never really thought to ask this but, how exactly do we so this?” He looked so cute when he was all bashful. “well we can start by doing this” I moved myself down his lap and made myself comfortable between his legs.

I gotta give it to him, he’s rather well endowed. He gave me a questioning look and I think he was even about to say something, well that was until I gave him a good long lick. I felt his pelvis tense as he gasped.

Magic has a rather funny taste, it tends to reflect the soul it belongs to. Papyrus was a strange mix of sweetness and a saltiness that I couldn’t compare to anything else other than pasta sauce. Ok, pushing that though down right now, back to the blow job.

I took him into my mouth slowly. I could hear his soft groans as I bobbed my head taking him in slowly. “Brother this feels, strange” “its ok paps, just relax and enjoy it ok? if it gets too weird then tell me to stop” He thought on it a moment before he nodded to me.

I looked down at his magical member and returned my attention to it, taking it into my mouth I rubbed small circles on his pelvis. Bones while plenty strong are also surprisingly sensitive, the gentle contact has him moaning and bucking his hips in pleasure.

I took him as far as I could before without choking, it was difficult with him bucking his hips like that. I managed to hold him down with some effort but I doubt he was gonna last much longer.

“Sans, I feel something’s coming” I took him about half way in and sucked hard. He came hard in my mouth as he threw his head back, he was gasping as I coughed and gagged. Not a bad flavor Paps, not bad at all.

Paps seemed to be coming back to his senses as he blinked blearily at me for a moment. “Wowie, that felt great.” I smiled at him “yeah bro it was good for me too. if your done i’ll go take care of myself and we can call it a night” I rocked forward to get off of the bed, it’s awkward shape made a quick escape impossible.

I felt Papyrus grab ahold of my wrist before I could get off the bed with a horrible blush to his cheeks. “Hold on brother, that doesn’t seem very fair to you. Is there any way I could, well help?” I felt my own blush return in full force. He was trying so hard to sound casual that it almost made me chuckle.

I could only look in in the face for a second before I turned away. I couldn’t face him when I asked this, I just couldn’t. “well paps if you really wanted to help we could try going all the way.” His brow just furrowed in confusion at my comment. “All the way to where brother?”

I huffed softly, sweet naive Papyrus. “i mean we go all the way, you bend me over and give me a good plowing. You stick your magic rod into me from my other end.” It took him all of 2 seconds to catch my drift this time. “oh. Oh, OH! You mean like that, oh well ok then sounds fine to me then.”

I looked at him to try and tell if he was actually serious or not but besides being what I’m pretty sure was a new shade of red, he seemed completely confident in his decision.

Well, ok then. I was getting ready to get onto his lap when he stopped me. “Nyeh, hold on Sans, my head keeps hitting the back of the bed. We should move this elsewhere.” I raised a brow at that. He sat up and grabbed me then lifted me off of the bed and took me over to the table that had all his carefully placed action figures.

He sweep an arm across the table and sent his precious action figures flying to the floor. “paps?! those are your favorite toys!” He placed me down on the table softly not seeming to pay the toys any mind. He planted another kiss on my lips before he started kissing down my neck.

“mhh paps! your getting good at this.” I lifted my hips a little and gave myself a few pumps “paps stop teasing already, come on give it to me!” I was starting to get impatient with him as he pulled away from me and blushed.

“Um ok then. I’ve never done this before” I kissed him and turned myself over, he grabbed my hips and pulled me closer to him. I felt him as he rubbed himself against my opening. 

I gritted my teeth as he started pushing in, damn he’s big! I could feel him pushing in, he’s a lot bigger than Grillby that’s for sure. He grunted as he pushed himself all the way in “Sans! Your so tight and hot I think I’ll go crazy!” I smiled at him as I looked back at him over my shoulder “and your the biggest i’ve ever taken, now give it to me”

He started to thrust into me in short and shallow thrusts, he was trying to be gentle with me I know but honestly I’m not that fragile. I grunted and thrusted myself back against him to get my point across. Paps didn’t seem to get the message, he was a virgin after all so I can’t expect him to fuck me like Grillby did without any guidance at all now could I?

“paps I want you to give it to me harder, I want you to be a little more rough with me” He looked concern “Are you sure brother? I don’t want to hurt you after all.” “it’s ok paps, i’m not gonna break that easily you can be a little rougher.”

He gave a few harder deeper thrusts that made me moan aloud, he seem to be starting to get the idea of what I really wanted. He didn’t quite get the rhythm down as he thrusted into me rather erratically, I thrusted my own hips back to try and better guide him into the pace.

He drove himself into me deeper and harder that had me groaning as he bent over and held onto me tight as his moans became louder and louder along with his erratic thrusting as he came in me hard. I gave myself a few pumps before I came all over the underside of his table.

I gasped quietly as his weight had me pinned to the table along with his still warm glow of magic inside of me, he was breathing hard into my ear as he tried to catch his breath. “Wow.. wowie. That was good, wasn’t it brother?”

I looked at him with a tired smile “yeah paps. it was good.” I could help him to improve later, we have plenty of time. I hoped.

He pulled himself out of me stumbled back allowing me to get to the floor “hey paps, i’m gonna take a shower and head to bed. wanna join me?” “Sure brother, that sounds nice”


	2. Chapter 2

**Summary for the Chapter:**

> I decided to add another chapter to this just for fun

**Notes for the Chapter:**

> Hey folks I decided to add another chapter to this as I've been trying to push through another writers block as well as trying to find where my bunnies hid my razor blades (I make costumes and certain fabrics have to be cut with a razor blade or else they look all choppy) and am trying to get this one costume finished and sent out before the holidays hit. As always expect edits over the next few days, why over the next few days? Well I don't always catch onto errors in the editing process though I have become better about it now a days but they still manage to slip through.
> 
> ~Enjoy

I woke up with a pained groan. Oh sweet lord who went to town on my ass last night? I shifted myself to sit up on my elbows and see who else was in my bed with me.

I thought my soul had stopped beating for a second when I laid eyes on Papyrus whom laid curled up next to me and it all hit at once. I had sex with Papyrus last night. Ohshitohshitohshit! Sans! What the hell have you done?! You took advantage of your younger brother you moron! You asshole, you … monster.

How could you take advantage of your naive, sweet, trusting brother?! I have to make it up to him somehow but how could I? I looked down at him with a grimace, he was sleeping soundly next to me and the mess that was my room, his race car bed having been too narrow for the both of us to sleep on comfortably last night.

I slowly and quietly sat up and removed myself from Papyrus’s sleeping grasp and crept out of my room only after I pulled on a pair of shorts and a dirty old shirt and left the room.

I quietly made my way down to the kitchen and started a pot of coffee. I pulled open the old refrigerator door and pulled out a few eggs, some bacon and the creamer and kicked the door shut behind me. I pulled out one of the many old pans that we owned, I think this one was one of my favorites that we had fished out from the garbage dump because it was both a nice size and it was in fairly good condition when I had found it.

I cracked open two eggs and fished out some bread that was a few days away from going stale and popped it into the toaster, on another burner I set the bacon to start cooking. I walked over to the table and sat down in an old chair that gave a loud squeak of protest, it was around the age that it was threatening to give out once and for all. I’ll have to go find a new chair soon, this wouldn’t be the first time we’ve had a chair break out from under one of us.

I walked over to the cabinet and fished out an old mug when the coffee pot finally finished brewing the new pot. I had finished plating the food and dumping a couple spoons of sugar into my coffee when I heard a sleepy Papyrus calling out for me “i’m in the kitchen paps.” I heard him make his way down the stairs with slow dragging steps, he still hadn’t fully woke up yet so it took him a few minutes to join me at the table.

We ate in relative silence with Papyrus eating happily and with me not having enough courage to touch on the topic muchless even look him in the eye. Today was his day off and Undyne was on a date with Alphys today, the weather outside has taken a nasty turn for the worst with the wind whipping around in a bone chilling blizzard.

“How is your morning brother?” I froze with the fork midway to my mouth. I sighed and set it back down on my barely eaten food and took a sip of my lukewarm coffee before I had finally built up the nerve to talk to him. “papyrus, … i’m sorry.” He looked at me with a cocked brow with his head leaned to the side.

This is going to be much harder than I thought it would be. “papyrus i’m sorry about last night. i took advantage of you, i shouldn’t have done that. i took advantage of your trust in me as your big brother and i used you. there are not enough words to say how sorry i am.” I felt myself shaking as I stared down into my cup unable to face him. He’ll hate me now, it’s what I deserve none the less.

He remained silent, he refused to talk to me. I knew this would happen, he would leave and never want to see me again, in one stupid, stupid, stupid move I ruined it all!

“Sans? Sans will you look at me?” I refused to look up from my cold cup of coffee until he grabbed my chin and forced me to look him in the face. I still refused to meet his eyes but he continued on anyways. “Brother, what are you talking about? You haven’t taken advantage of me, at least not to what I have seen.”

I clenched my eyes shut “papyrus I took advantage of you last night, i shouldn’t have done that to you. i’m your older brother and you should be able to trust me, you did trust me and i took advantage of your trust and your body.”

I heard him grunt and let me go, I was expecting the slamming of a door whether it was the front door or to his bedroom. What I did not expect was him grabbing me from my chair and taking me to our couch where he set me down softly. “Sans since you refuse to look at me I’m just going to talk and I want you to listen to me alright?”

I gave a curt nod while staring down at my clenched hands as he continued “Sans I know I’m a bit naive and I don’t always catch onto everything as fast as I should but I’m not stupid. I agreed to what we did together because I wanted too. I could have easily have stopped you at any point and I know for a fact that if I said stop then you would have stopped.”

He rested a hand against my knee and I finally looked up to his face still not quite meeting his eye. “Sans, I love you. I would like it if we could continue this relationship but if it makes you this uncomfortable then we can stop.”

I gathered up all of my resolve, I’m gonna be a better brother from now on, Papyrus deserves that much. I looked him in the eye with the plan of ending this firmly in mind but as I looked in his eyes I lost all of my nerve, my rejection dying on my tongue.

I found myself babbling dumbly as I tried to end the relationship before it really started but I just couldn’t. He grabbed the sides of my head and pulled me into a kiss, I put up a half hearted fight before I gave in and kissed him back.

He pushed me to where we could lay down on the couch comfortably. I snaked a hand up his loose pajama top as he started pulling at my shirt, I felt something pressing against my lower leg and blushed down at the obvious bulge in his pants, I felt my own growing need straining in my now all too tight shorts.

“I enjoyed last night brother, I think it might be fun if we did it again” I smiled and sat up on my elbows “well paps i’m thinking we do something a little different this time, you lay down on the couch and i’ll ride you.” He cocked a brow but did as he was told.

I pushed him to lay down and grounded myself against him hearing his sweetest groans of pleasure urging me to continue. “mmhn paps. Your going to have to take off your pants or at least pull them down some for me.”

Papyrus nodded and shuffled around trying to loosen his pants, I watched him struggle for a few minutes before I stepped in to and help him out. After we had pulled his pants loose from where they had gotten caught on his hip bones that I started to work on taking off my own shorts and rubbed his magic against my hole, dammit he’s big. I grunted and slowly inserted it into me slowly with a groan of pain, Paps didn’t seem to catch onto that as he gripped my hips and pushed himself the rest of the way in.

I threw my head back as he held me down, he was clearly intent on fucking me senseless. I had other plans in mind so I slapped his lightly hand and placed both of my hands on his lower waist to sort of hold him in place

My ass was still pretty sore from last night, Papyrus had really done a number on it. I groaned as I felt every inch of him pulsating inside of me, he was so warm. I began lifting myself up and going back down slowly enjoying every second of the much slower pace.

He sat himself up enough to kiss me softly a gesture which I gladly returned. I set a lazy pace for myself which seemed to annoy Papyrus, I heard him grumble about me being lazy even in sex. I couldn’t help but laugh at that as I picked up the pace a little for him, he was so warm inside me that I had little shivers of pleasure running through my body in response.

I could hear his soft moaning mixing in with my own as I rose up and dropped back down on his hot cock, I could feel his cock twitching inside of me that was going to drive me crazy. “oh fuck paps!” I jerked as I felt him rubbing up against a particularly sensitive spot inside of me, he noticed this and held my hips down and started grinding against that spot.

“You like that don’t you? You like it when I grind into you with my huge cock?” I didn’t get a chance to respond when I felt him shift under me, he pulled me off of himself and pushed me up and turned me to where I was on my hands and knees. I looked at him over my shoulder about to ask what he was doing when I felt him push back into me.

I gasped as he leaned over me gripping the arm of the couch to balance himself as he started to thrust into me. His pace was only a little faster then the one I had set for us earlier, his thrusting wasn’t as jerky or as aggressive as it was last night.

I moaned his name as he started thrusting into me with long smooth motions “ummm paps, so good! don’t stop!” I couldn’t help but drool a little as he thrusted into me, the new angle was letting him thrust in me deeper than before. “Hah, umnn, Sans your so tight, I think I’m going crazy” he was panting hard in my ear as he ground his hips against me.

I looked back at him over my shoulder and pulled him into a kiss, with him being far taller than me having made this sort of difficult for the both of us. “mmh paps, your getting good at this AH! Damn. i love you paps, i love you!” It was getting harder to think as he thrusted into me, my mind felt like it was slogging through a sea of mud made from lust and desperation. I couldn’t think too far ahead beyond that I loved him. I love him I love him I love him! I need him and I can’t lose him again, never again.

I pushed my hips back against him desperate to find release, I have to come, it hurts so bad I need it! “paps I need to see your face” he stopped only long enough to turn me over so that we could face each other.

His face had a heavy blush and he was dripping with sweat, I saw the lust burning in his empty eye sockets that only made me harder and want to come even more. I hugged him and buried my face in his neck as his thrusting became more erratic as he was nearing his orgasm, I felt my own coming painfully close but was staying just out of reach.

“Sans I’m going to cum, take it all!” I clutched to him tight as the pressure that had been building up finally blew, I had honestly whited out for a few minute as I let the flood of uforia flood over me in crashing waves that keep my mind drowning in sheer bliss. I felt a great weight on myself as well as a flood of heat and a deep rooted pressure in my ass, the warmth and the feeling of fullness keep my mind lost in the haze of good sex.

It had taken a few good minutes before my mind had managed to dig itself free from the mud enough to find that Papyrus had collapsed against me and hadn’t pulled out yet which I was fine with but his weight while warm was making it difficult for me to both catch my breath and keep from getting another raging hard on.

While I love sex there was only so much of it I could take so many times in such a short span of time could definitely put my health in jeopardy. I pushed at his shoulder and patted at his face to get his attention, he gave a weak mutter of acknowledgement in response. “paps, while i love you and how warm you are, your heavy. please get off before i start making puns.

I heard him growl and finally sat himself up and slowly pull himself out, the pop and feeling of both the loss of fullness coupled with the warm flood of his magic that dripped out of me to pool around my hips felt incredible. “i love you papyrus” he smiled at me with a gentleness that made my soul ache. He was so kind, my cool bro. “I love you too Sans.”

We shared a kiss before I pulled away from him to take a shower, I heard him mumble about cleaning up the mess we made. I almost wanted to stop him but I knew it wouldn’t do any good with him being such a neat freak and all, cleanliness is important to being a future royal guardsmen or something like that.

I looked down at him from over the railing one last time with a tired smile before I walked into the bathroom to take a long hot bath.

**Author's Note:**

> I love getting comments on what more you people might want to see as well as kudos =^^=
> 
> Edit: hello hello folks! So it has come to my attention that my story shares similar elements to an undertale comic by tousledpelvis, I looked over the comic where it was both Sans and Payrus on his bed. Yes my story is based off of a comic and pulls elements from it but it wasn't the one with the bed, it was a different comic the had Papyrus walk in on Sans while he was all hot and bothered then ran out after Papyrus. Thats about where the similarities end, I do try to give my stories my own style and while this is based off of a comic I didn't intend for it to step on its toes here. If I could find the name and artist that I refferenced from I'd be more then happy to give them a credit, I would have but the comic was entirely in Spanish so I had difficulty reading it muchless finding who made it, if anyone knows who the artist is or what the comic is called I'd be more then happy to credit them or even make changes so as not to offend. It's never my intention to plagiarize anyone's work and while some of my stories may be similar to others I never try to copy and make minor edits to rip anyone else's work off. This story is also similar to one of my other stories called 'A rough night', the first chapter anyways.


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